There are quite a few operating systems which have moved beyond the simple hobby operating system stage, onto a more lasting plane of existence. AROS, ReactOS, SkyOS, Syllable, Haiku; they're no longer basement products, coded by a single programer - they are now projects in which a lot of people have invested time, and possibly money too. They won't go away any time soon. The last few days have seen news on three of these systems: ReactOS, SkyOS, and Syllable.